Method for concentrating carotenes



Patented Oct. '28, 1952 -iuErHonmR CONCENTRATING GABOTENES Herbert J. Passino,"Englewood, N. 'JL," a'ssigno r to- The M. W. Kellogg'Company, Jersey City, N. 'J.,'

' "a. corporation of Delaware s ,No Drawing. Application.Eieptember29, 7 Serial No. 118,713

- 4- Claims. (01. 260-660;

,1 This invention is a method 'for concentrating carotene from palm oil by'heatingthe palm oil to bring about a split of carotene .complexes and then concentrating thecaroI-tene by solvent extraction with a low boiling solvent under par-a elevated temperature and pressure conditions (i. e. in. the paracritical range) tq cause. th solvent and oil mixture to form two phases. Although both phases contain solvent, the lighter and heavier phases are referred to as extract and rafiinate phases respectively because of the relatively greater quantity and percentage of solvent in the lighter phase. As disclosed in the Larner patent, the carotenes tend to concentrate in the bottoms fraction. It has been found, however, that substantial percentages of carotene are lost to the extract and that a degree of concentration of carotene in the raffinate varies considerably from one oil to another, or for the difierent portions of the same oil which have received various pretreatments. Further study indicates that the carotene can exist in the oil in either of two states: (1) as a complex in loose combination with protein and other material and (2) in a simpler or more or less free state. The carotene complex which is ordinarily the predominant form in raw palm oil tends to concentrate in the raflinate phase, whereas the simpler carotene complexes are lost to the extract phase. It is the object of the present invention to pretreat the oil to break down substantially all of the complex carotene so that it can be concentrated in the extract phase. It has been found possible to accomplish this object by heating the oil for a period of 10 minutes to one hour at .a temperature between 200 to I heated'and will vary greatly j-from oil to oil or even for the same oil after varying holding periods under certain storage conditions. A temperature of more than 200 F. appears to be more effective than thetemperatures encountered in the ordinary paracritic'al fractionation itself. Temperatures over 500 F. tend to destroy val- 'uable' constituents 'of fthe' oil. Temperatures within this range are usually satisfactory with the residence time required being shorte for the I higher. temperatures. Th optimum time and temperature conditions for'preheating palm oils in general can only be specified as ranges. Because of the great variation from one oil batch to another, the optimum conditions for a particular oil must be determined by testing samples. It is convenient in most cases to neutralize the oil with amild alkali While it is undergoing heat treatment.

Immediately after the oil has'been heat treat- -ed; it isintimately contacted with a relatively low boiling solvent under paracritical conditions to fractionate the oil into extract and raffinate phases. The low boiling solvent employed is usually propane, but it may be any of the liquefied normally gaseous hydrocarbons. Also, there are many other solvents which are not hydrocarbons but which are suitable for iractionating an oil under paracritical conditions. Carbon dioxide, dimethyl ether, halogenated hydrocarbons, such as dichlor-difluormethane, may be employed. It is only necessary that the solvent be chemically inert with respect to the reactants under the conditions of the process and that the solvent have a critical temperature not higher than about 450 F., although hexane which has a critical temperature of slightly above 450 F. may be used. The reason for the critical temperature limitation is that the advantages of the so-called .paracritical fractionation are attained by contacting the oil and the solvent in a temperature range near the critical temperature of the solvent in which the density of the solvent decreases rather rapidly with increasing temperature. Decreasin density is accompanied by decreasing of solubility of the oil in the solvent. This range usually extends from about F. below the critical temperature to a few degrees above the critical temperature. Thus, it'is relatively easy to select a temperature in the paracritical range for fractionating the oil into any desired per oentage of extract and percentage of rafiinate.

In the concentration of carotene from the heat treated palm oil, as in the case of most paracriticalfractionations, one must reach a com- 3 promise between recovery and concentration. For a particular heat treated palm .eil a very high concentration may be obtained by fractionating at a relatively high paracritical temperature'but substantial loss of carotene to the raffinate may be experienced. Fractionation at a =low'e paracriticaltemperaturewill reduce the carotene concentration obtained but increase the percentage of carotene recovered from the oil. The precise temperature at which fractionationfwill be-carried out and the degree of concentration of iecovery which will be sought in a particular case I claim: I v I 1. 'A me'tho'd ror'conce'ritratmg carctene Ti'l'itki an oil containing carotene complexes 'df'SuldStJhtially higher molecular Weight "than caititne, which includesthe steps or; ne'aring'said' onto a temperature'hetwenflflflf'F; anaso'o F. for a period o;f '10 minutes to one hdrir'to convertsaid carotene com'p'lexesto carotene'forms of substantially lower molecular weight; then contacting said on with a solvent having a critical temperature less than 450' F. at'temperatures in 'a range of temperatures near the critical temperature'in which solubility decreasesas temperature increases to iractionate said oilinto extract and rafiinate phases, saidextractphase containing an 4 oil concentrated in carotene; and recovering from said extract phase a concentrate of carotene in a form of substantially lower molecular weight than said original carotene complexes.

2. A method for obtaining a concentrate of --carotene -"from' a "palm' oil contai'nmg substantial amounts or carotene in a complex form of substantially higher molecular weight than carotene, which method includes the steps of: heating-said I'p'alihhil to a temperature between 200 FAa'Jnd 500 F., for a period of 10 minutes to one hour to break complexes into carotene forms of icvrernrcieemar weight than said original carotem-co pl xes; then contacting said oil with a solvent having 'a critical temperature less than 45G?- F.,- at temperatures in a range of temperatures near the critical temperature of said solvent in'which solubility decreases as temperature increases to fractionate said oil into a raiilnate phase and an extract phase containing an oil :con'centra't'ed in saidjlca'roterie forms of molecu- 'l'ar weight 'substantiallylowe'r than said 'Qri'ginal carotene complexes; "and recovering atarotene concentrate from saidextractphase.

"'3. A method as described in claim 2 inwhich the solvent is propane. V y 4. "A 'm'ethodas described inclaim-Z in which the oil is subjectedto neutralization with a mild alkali'while tinder'gOing heat treatment.

-HERBE'RT 1J.=-PASSINO.

REFERENCES "CITED The following references fare of record in the file of this patent:

UNITED STATES PATENTS Number Name 'Date 12,412,707 Barnett Dec. 17,1946 2,432,021 Larner Dec; 2, 194? 

1. A METHOD FOR CONCENTRATING CAROTENE FROM AN OIL CONTAINING CAROTENE COMPLEXES OF SUBSTANTIALLY HIGHER MOLECULAR WEIGHT THAN CAROTENE, WHICH INCLUDES THE STEPS OF : HEATING SAID OIL TO A TEMPERATURE BETWEEN 200* F. AND 500* F. FOR A PERIOD OF 10 MINUTES TO ONE HOURS TO CONVERT SAID CAROTENE COMPLEXES TO CAROTENE FORMS OF SUBSTANTIALLY LOWER MOLECULAR WEIGHT; THEN CONTACTING SAID OIL WITH A SOLVENT HAVING A CRITICAL TEMPERATURE LESS THAN 450* F. AT TEMPERATURES IN A RANGE OF TEMPERATURES NEAR THE CRITICAL TEMPERATURE IN WHICH SOLUBILITY DECREASES AS TEMPERATURE INCREASES TO FRACTIONATE SAID OIL INTO EXTRACT AND REFFINATE PHASES, SAID EXTRACT PHASE CONTAINING AN OIL CONCENTRATED IN CAROTENE; AND RECOVERING FROM SAID EXTRACT PHASE A CONCENTRATE OF CAROTENE IN A FORM OF SUNSTANTIALLY LOWER MOLECULAR WEIGHT THAN SAID ORIGINAL CAROTENE COMPLEXES. 